Embolic coils have been used to stop undesired blood flow, as in, for example, the treatment of aneurysms, arteriovenous malformations, traumatic fistulae and in tumor embolization. These conditions require that the blood flow through a portion of a blood vessel be stopped, for example by introducing an artificial device into the vessel to slow the flow, and by letting the natural clotting process form a more complete blockage of the blood vessel with a clot.
Embolic coils can be used to form a blockage in a vein or artery to treat conditions like those listed above. These devices have become increasingly common in procedures to block the flow of blood by promoting formation of a clot in a desired location. Embolic coils are made from a bio-compatible material, such as platinum, to minimize the problems associated with tissue irritation and rejection. These coils are often shaped as complex three dimensional curves that fill in portions of the blood vessels and slow blood flow therein. Often, polymeric fibers are added to the metallic coils to enhance the coil's thrombogenicity, which is the coil's ability to promote formation of clots.
Embolic coils are typically introduced into a blood vessel by using a microcatheter which extends from a proximal point outside the patient's body to a distal point near the embolization site. An introducer sheath containing the coil is used to carry and protect the coil prior to insertion into the patient, and also to transfer the coil to the microcatheter. From the introducer sheath the coil is pushed into the microcatheter and navigated to the embolization site, where it is deployed from the microcatheter. It is often beneficial to pre-hydrate the coil before insertion into the microcatheter to lubricate the coil, so that it travels more easily to the embolization site. In addition, the fluid used to lubricate the coil may be medicated to increase the thrombogenic properties of the coil, reduce infections, or to address other needs.